Speed reducer



1939. J. w. KITTREDGE 2,168,164

SPEED REDUGER Original Filed July 51 1955 3 Sheets-Sheet 1 Ar O Aug. 1,1939. J. w. KITTREIIDGE SPEED REDUCER s Shets-Sheet 2 Original FiledJuly 31, 1935 I fr lleqfor 'wa/azalyq Patented Aug. 1, 1939 UNITEDSTATES PATENT OFFECE Continuation of application Serial No. 34,079, July31, 1935. This application November 6, 1937, Serial No. 173,251

21 Claims.

This application is a continuation of my prior patent application forSpeed reducers, Serial No. 34,079, filed July 31, 1935.

Electric motors and some other motors run I preferably at high speed,generally at much higher speed than the machines they drive, and it isnecessary to reduce speed by belting, gearing or other meanstherebetween. In some cases, it may be necessary to increase the speed.Again, gears in general are unyielding, and spring gears and springcouplings have been devised to relieve shock. It is diflicult to getsuflicient spring material into a rapidly rotating part to give itappreciable cushion or yield without making it big and cumbersome, andwithout having its weight slightly eccentric in some position of thespring.

The objects of my invention are:

1st. To have the reducer supported at one end by a shaft and in drivingengagement therewith through gears symmetrically arranged therearound,thus effecting uniform distribution of load, and turning moment onlywith no transverse pressure on the shaft, and thus also eliminatingunnecessary shafts placed end to end, and so economizing room.

2nd. To have the opposite end of the reducer supported by a flexiblejoint to compensate small errors of alignment.

3rd. To cushion the drive by resilient non-rotating parts engaging thereaction member; to have them big enough to give ample resilience withsmall motion and fatigue of the parts themselves; to have themnot exerttransverse pressure and friction on rotating shafts; and to have as themnot cause undue friction or wedging of the gear teeth.

4th. To have the reducer operate in forward and reverse directions; tohave the reaction member oscillate on its supports; and to have theleverage and therefore the force of the resilient parts increase as thereaction member moves from its neutral position.

5th. To have all parts simple to construct and strong and durable, andtohave them easily accessible when assembled for use.

I attain these objects by the mechanism shown in the accompanyingdrawings in which:

Fig. 1 is a vertical longitudinal section on line l--l of Figs. 2, 3 and4. Fig. 2 is a plan with parts in section on line 2-2 of Fig. 1. Fig. 3is a cross-section on line 33 of Fig. 1. Fig. 4 is a cross-section online 4-4 of Figs. 1 and 2. Fig. 5 is a similar section showing adifferent position of casing and lever. Fig. 6 is a vertical 5;longitudinal partial section similar to Fig. 1, but

enlarged to show the bearings more clearly. Fig. '7 is again a verticallongitudinal section similar to Fig. 1, but stripped down to itsfundamentals in order to show them more clearly Fig. 8 is a verticallongitudinal section similar to Fig. 'l, 5 but showing a few more of thesalient parts.

A given part carries the same number throughout the several views. Forclearness of description, a given part is designated by a numeral, as4|, and different edges or faces of that part by that numeral withletters, as MA, ME, MG, etc. Two parts cast together and integral arecrosshatched alike.

Bearing bracket 31 is bolted to base 32 by bolts 34. (See Fig. '7.) Cap54 is screwed down on bearing bracket 3| by bolts 56, and it clampssleeve tightly in place. Hollow shaft 51 runs in internal bearing 55B ofsleeve 55, and this is preferably a ball bearing-62 as shown in Figs. 6,7 and 8. Shaft51 is slow speed, and the object of the ball bearing isnot so much to reduce friction as to permit slight misalignment. Shaft44 runs inside hollow shaft 51.

Motor 30 is bolted to base 32 by bolts 33. Motor shaft 20 carries gear2! held to said shaft by key 22. Spider 43 with three arms is keyedrigidly on the end of shaft 45 by key 65. Three bolts 46 are screwedtightly into spider 43 (with sleeves 41 as shown). On sleeves 41, runthree gears 23, preferably 'degrees apart. Gears 23 mesh with motor gear2| and are supported by said motor gear. (See Fig. 3.) Gears 23, throughbolts 46 and spider 43, support the end of shaft 44. Thus shaft 44is'supported at one end by motor shaft 29 and motor gear 2!, and at theopposite end by bearing bracket 3i, preferably through ball bearing 62.As gear 2 [supports the adjacent end of the drive through its engagementwith the three gears 23, it must always drive equally on said threegears, effecting uniform distribution of load, with no transversepressure on shaft 2i except the weight of the drive. And this weight isusually small compared with the driving torque.

Each bolt 46 has a sleeve 41 an-d'a washer 48, with clearance to allowgear 23 to run freely; Sleeve 4'! interlocks with washer 48 and withspider 43 as shown in Fig. '7. As bolt 45 screws tightly down, it locksthe sleeve and the washer to the spider, and rotating gear 23 has notendency D0 to unscrew the bolts.

The reaction member.Annular gear 25 is bolted to diaphragm 21 by bolts28. Casing members 35 and 35, preferably steel stampings, are fastenedrigidly to diaphragm 21 as by welding,

and thus form one rigid piece, the bottom half of the casing. Casingcover 31, also a steel stamping, is bolted to bottom 35 and 36 by bolts38. And casing end piece 4| is bolted to casing 35 and cover 3! by bolts42. Annular gear 26, diaphragm 21 and casing members 35-363'|4| are thusfastened rigidly together. They are restrained from rotation ashereinafter described, and we consider them to be the reaction member.The casing is adapted to hold oil.

Sleeve 55 has, beside its internal bearing 55B above described, anexternal bearing 55A shown in Figs. 6, 7 and 8. Ball bearing 63 carriesend piece 4| on external bearing 55A, and thus carries the adjacent endof the reaction member.

Shaft 44 runs in bearing 21A of diaphragm 21. And the three gears 23above described mesh with annular gear 26. Gears 23 may carry theadjacent end of reaction member 262|-3536 374| by tooth contact withgear 26, as if the bearing 21A were bored excessively large. Or, if saidbearing is close fitting and the gear, teeth have large clearance, saidgears 23 may carry the adjacent end of said reaction member through hubor bearing 27A. In any case, the end of the reaction member is supportedby gears 23 and, through them, by motor gear 2| and motor shaft 26. Asdriving gear 2| drives, gears 23 rotate on their own axes and alsofollow around annular gear 26 and are thus planetary. I

Two levers 58 and 59 are pivoted on pins 66 which are fixed in feet 3 Aof bearing bracket 3| The levers are connected at the top by tensionspiral spring 6|. Two lugs MA and MB are integral with end piece 4| ofthe reaction member. At rest or running idly, reaction member 4| is inits neutral position, the upper ends of lugs MA and MB engage the twolevers, and the levers engage lugs 3|B of bearing bracket 3|. When poweris being transmitted, reaction member 4| moves forward or back, pressesone lever as 58 back from lugs 3|B, and stretches spring 6|. (See Fig.4.) As the power and the torque increase, they press the lever fartherback as in Fig. 5. As the'torque increases, the point of contact and theline of force move from the upper end to near the lower end of lug 4| A,approaching the fulcrum 66 and receding from the fulcrum 55A. With bothlever arms changing, the spring 6|, with small amount of stretch,controls a large increase of power. This not only takes care of variableamounts of power regularly transmitted, but gives appreciable yield andrelieves shock when a large amount of power is suddenly applied. And thetotal stretch of the long spring causes a very small amount of stretchin each coil thereof, not enough to cause great fatigue. The levers 58and 59 engage the lugs MA and MB in line with bearing 55A, as shown inFigs. 1 and 2. The heavy pull of the spring is thus transmitted tostationary bearing 55A on which is only a slight oscillatory movement.None of that pull is transmitted to the running parts inside thebearing; none of it is transmitted to the support on the rapidly runningmotor shaft 26; and none of it tends to keep the gears from runningcorrectly on their pitch lines. And the figures show the mechanismsymmetrical on forward and backward drive.

To disassemble the reducer, release spring 6| and take off cap 54 andcover 31. Then remove bolt 46 (uppermost bolt as shown in Fig. 1) andslip out gear 23 between gear 2| and annular gear 26. Then turn thereducer half over and lift it out.

Any kind of drive may be used to drive hollow shaft 51 from shaft 44. Orhollow shaft 5! may be eliminated altogether and shaft 44 may be thedriven shaft.

In the embodiment herein shown, annular gear 66 is bolted to diaphragm2'! by bolts 28. Shaft 44 has integral with it an eccentric 44A. Saideccentric carries gear 61 which meshes with annular gear 66. Annulargear 51A is rigid with hollow shaft 5?, and is preferably cast solidthereon. Shaft 44 has integral with it another eccentric 44B. Saideccentric carries gear 68 which meshes with annular gear 51A. Gears 6'!and 68 are held to the same angular motion by ring 69. Rigid in ring 69,are two pins 690 and 69D projecting from one side thereof, and two otherpins 69A and 69B projecting from the opposite side thereof, said pinsbeing 90 degrees apart as shown. Pins 69C and 69D carry rollers H whichrun in radial slots in gear 61, and pins 69A and 69B carry rollers 16which run in radial slots in gear 68. And these cause the gears 61 and68 to turn together always. The two pairs of meshing gears are indifferent ratio, and this transmits rotary motion from shaft 44 tohollowshaft 51. Shaft 51 is then the driven shaft with keyway 51B for gearor-coupling.

The drive thus comprises two sets of gears in sequence. Spur gears 2|and 23 and annular gear 26 are the first set. Spur gears 61 and 68 andannular gears 66 and 51A are the second set. And shaft 44, the drivenmember of the first set, is the driving memberof the second set.

In the description and claims herein,. gear train, drive connection, andsimilar expressions are used to mean the direct power transmittingmembers. In general, they are rotating members. But these expressionsare not used herein to mean or to include the reaction member. Aroundand about may mean an inside arrangement as well as an outside. That is,gears 23 are arranged around or about annular gear 26 just as truly asthey are arranged around or about spur gear 2!. Carried and supportedmean held in working position, though not necessarily by upwardpressure. For instance, if any one of the gears 23 were taken off, theother two gears 23 would not mesh properly with gear 2| and drive.Hence, the three gears 23 are carried or supported by the gear 2|, eventhough the gear 2| presses downward on one .of them. Gear member is usedmore broadly than the term gear, and means herein a single gear, or agear mounted on a shaft, two gears integral or mounted on a shaft, as iscommon practice, especially in planetary gearing, or other simplemounting of gear. Connection and engagement are used broadly to meanmembers co-operating, as lever 58 and reaction lug 4|A; not necessarilyinterlocking members. Motor shaft is used to mean the shaft of any kindof motor; not necessarily an electric motor as shown.

It will be understood that my speed reducer may be made in many formsand styles, and still come within the spiritof my invention. Thedescription is to be broadly construed. Hence, I do not limit myselftothe embodiment herein shown, but only by the following claims.

Having thus described my invention, I claim: 1. A speed reducercomprising a motor shaft; a bearing; a reaction member; a gearconnection from said motor shaft to said reaction member, said reactionmemberhaving one end adjacent said motor shaft and supported by saidshaft through said gear connection, and havingits opposite end journaledon and supported by said bearing, and said reaction member beingrotatable on said motor shaft and said bearing through a partialrevolution; a driven member; adrive connection through the gearconnection aforesaid from said motor shaft to said driven member; ayielding member in line with said bearing; and a connection from saidyielding member to said reaction member.

2. In combination, a gear train comprising a gear centered on the axisof said train and adjacent one end thereof, gear members in engagementwith saidgear, and said gear supporting the adjacent end of the trainthrough said gear members; a reaction member in engagement with saidgear members, said reaction member having one end adjacent said gearfirst aforesaid, and having that end supported by said gear through saidgear members; resilient means to restrain the rotation of said reactionmember; and a variable lever in said means increasing the restraint asthe torque increases.

3. A speed reducer symmetrical on forward and backward drive andcomprising a driving shaft;

a bearing; a reaction member, said reaction member including a casingadapted to hold oil, and having one end adjacent to said driving shaftand an opposite end journaled on and supported by said bearing; a gearon said driving shaft; three gears approximately 120 degrees apart andin mesh with the gear aforesaid; connections from said three gears tosaid reaction member, the driving shaft adapted to support the adjacentand of said reaction member through the gears aforesaid, and saidreaction member being rotatable on said driving shaft and said bearingthrough a partial revolution; a driven member; a gear connection throughthe gears aforesaid from said driving shaft to said driven member; ayielding member opposite said bearing; and a connection from saidyielding member to said reaction membera 4. A speed reducer symmetricalon forward and backward drive and comprising a motor shaft;

a driven shaft; a reaction member; a gear connection from said motorshaft to said driven shaft, said reaction member being in engagementwith said gear connection, having one end adjacent said motor shaft andhaving that end supported by said motor shaft through said gearconnection, and said reaction member being rotatable on said motor shaftthrough a partial revolution; a yielding member; a lever on the reactionmember in engagement with the yielding member, and the leverage variableas the reaction member rotates.

5. A speed reducer comprising a shaft; a reaction member having one endadjacent to said shaft; a connection from said shaft to theadjacent endof the reaction member, said shaft adapted to support said adjacent endthrough said connection, and said reaction member adapted to rotate onsaid shaft through a partial revolution; a second shaft; a driveconnection between the two shafts; a yielding member; and a connectionfrom the yielding member to the reaction member.

6. A speed reducer comprising a shaft; a joint flexible in alldirections; a reaction member; a gear connection from said shaft to saidreaction member; said reaction member having one end adjacent said shaftand supported by said shaft through said gear connection, and having itsop-- posite end in engagement with and supported by said flexible joint;a second shaft; a drive connection between the two said shafts throughthe gear connection aforesaid; a fixed member; and a" flexibleconnection from the fixed member to the reaction member.

'7. A speed reducer comprising a shaft; a joint flexible in alldirections; a reaction member; a gear connection from said shaft to saidreaction member; said reaction member having one end adjacent said shaftand supported by said shaft through said gear connection, having itsopposite end in engagement with and supported by said flexible joint,and said reaction member being rotatable on said shaft and said flexiblejoint through a partial revolution; a second shaft; a drive connectionbetween said shafts through the gear connection aforesaid; a yieldingmember; and a connection from said yielding member to said reactionmember.

8. A speed reducer symmetrical on forward and backward drive andcomprising a .motor shaft; a bearing having external and internalbearing surfaces; a reaction member; a drive connection from said motorshaft to said reac-- tion member; said reaction member having one endadjacent said motor shaft and supported by said motor shaft through saiddrive connection, and having its opposite end journaled on and supportedby said external bearing surface, and said reaction member adapted torotate through a partial revolution on said motor shaft and saidexternal bearing surface; a driven member journaled on said internalbearing surface; a drive connection from said motor shaft to said drivenmember through the drive connection aforesaid;

, a yielding member opposite said external bearing surface, and aconnection from said yielding member to said reaction member.

9. In combination, a driving member; a driven member; a reaction member;a reversible drive connection from said driving member to said drivenmember through said reaction member; said reaction member having aneutral position under no torque, a forward position under torque in onedirection, and a back position under torque in the opposite direction; ayielding connection from a fixed object to said reaction member in itsneutral and forward positions only; and a yielding connection from afixed object tosaid reaction member in its neutral andback positionsonly.

10. In combination, a driving member; a driven member; a reactionmember; a. reversible drive connection from said driving member to saiddriven member through said reaction member; said reaction member havinga neutral position under no torque, a forward position under torque inone direction, and a back position under torque in the oppositedirection; a yielding connection from a fixed object to said reactionmember in its neutral and forward positions only; a yielding connectionfrom a fixed object to said reaction member in its neutral and backpositions only; levers in said yielding connections; and the leverage ofsaid yielding connections increasing asthe said reaction member movesaway from its neutral position. I

11. In combination, a gear; a shaft member; a reaction member; a driveconnection from said gear to said shaft member through said reactionmember, said drive connection having one end supported by said gear, andsaid reaction member having one end adjacent said gear and supported bysaid gear through said drive connection; said reaction member having aneutral position under no torque, a forward position under torque in onedirection, and a back position under torque in the opposite direction; ayielding connection from a fixed object to said reaction member in itsneutral and forward positions only; and a yielding connection from afixed object to said reaction member in its neutral and back positionsonly.

12. In combination, a planetary gear traincomprising a gear rotating onthe axis of said train and adjacent one end thereof and planetary gearmembers in driving engagement with said gear; a reaction gear in drivingengagement with said planetary gear members; a yielding connection fromsaid reaction gear to a fixed object; and said gear first aforesaidsupporting the adjacent end of the mechanism through said planetary gearmembers.

13. In combination, a planetary gear train comprising a gear rotatingonthe axis of said train and adjacent one end thereof and threeplanetary gear members arranged around said gear and in drivingengagement therewith; an annular reaction gear in driving engagementwith said three planetary gear members; a yielding connection from saidreaction gear to a fixed object; and said gear first aforesaidsupporting the'adjacent end of the mechanism through said planetary gearmembers.

14. In combination, a gear train comprising a gear centered on the axisof said train and adjacent one end thereof, gear members in engagementwith said gear, and said gear supporting the adjacent end of the trainthrough said gear members; and a reaction member in engagement with saidgear members, said reaction member having one end adjacent to said gearfirst aforesaid, and having that end supported by said gear through saidgear members.

15. In combination, a gear train comprising a gear centered on the axisof said train and adjacent one end thereof, gear members in engagementwith said gear, and :said gear supporting the adjacent end of the trainthrough said gear members; a reaction member in engagement with saidgear members, said reaction member having one end adjacent said gearfirst aforesaid, and having that end supported by said gear through saidgear members; a yielding connection from said reaction member to a fixedobject; and said combination symmetrical on forward and backward drive.

16. In combination, a driving gear; three gear members arrangedtherearound, in driving engagement therewith, and supported thereby; a

driven member; a reaction member, said reaction member being inengagement with said gear and said gear supporting the adjacent end ofthe train through said three gear members; a reaction member inengagement with said three gear members, said reaction member having oneend adjacent said gear first aforesaid and having said adjacent endsupported by said gear through said three gear members; and a yieldableconnection from said reaction member to a fixed object.

18. A speed reducer comprising a motor shaft; a bearing; a gear trainhaving one end adjacent said motor shaft and supported by said shaft,and having its opposite end adjacent said bearing and supported by'saidbearing; a reaction member rotatable through a partial revolution and inengagement with said gear train; and a resilient connection from saidreaction member to a fixed object.

19. A speed reducer comprising a motor shaft; a bearing; a gear traincomprising sets of gears in sequence, having one end of said trainadjacent said motor shaft and supported by said shaft, and having itsopposite end adjacent said bearing and supported by said bearing; and areduction member in engagement with said gear train.

20. A speed reducer comprising a motor shaft; a joint flexible in alldirections; a gear train having one end adjacent said motor shaft andsupported by said shaft, and having its opposite end adjacent saidflexible joint and supported by said joint; a reaction member rotatablethrough -a partial revolution and in engagement with said gear train;and a resilient connection from said reaction member to a fixed object.

21. A speed reducer comprising a motor shaft; a joint flexible in alldirections; a gear train'com-' prising sets of gears in sequence, havingone end of said train adjacent said motor shaft and supported by saidshaft, and having its opposite end adjacent said flexible joint andsupported by said joint; and a reaction member in engagement with saidgear train.

JOHN W. KI'I'IREDGE.

